Exam 4 Microbio

Chapter 21, 22, 24, 25, 26

thin outer portion of skin; composed of layers of epithelial cells

Epidermis

waterproofing protein coating outer layer of epidermis

Keratin

inner, thick portion of skin; composed mainly of connective tissue

Dermis

___________ provides moisture and nutrients for growth

Perspiration

Contains salt that inhibits microorganisms

Perspiration

__________ breaks down bacterial cell walls

Lysozyme

found in bodily secretions on skin, breaks down peptidoglycan layer of bacteria

lysozyme

the skin has _________ peptides

Antimicrobial

the moist tissues that line the inside of the body.

mucous membranes

contain glands that produce mucus

Mucous Membranes

There are tightly packed epithelial cells attached to the ______________, a layer of extracellular material

basement membrane

Cells that secrete mucus, a thick, slippery fluid that acts as a lubricant to prevent tissues from drying out. Some of these have cilia

epithelial cells

these membranes of often acidic and folded to maximize surface area. They provide attachment for some viruses

mucous membranes

Membrane of eyes washed by tears containing ________

lysozyme

Resistant to drying and high salt concentration

Normal Microbiota of the Skin

2 types of gram positive cocci that live on skin

Staphylococci and Micrococci

can handwashing get rid of normal micrbiota?

no, they quickly repopulate

what areas of skin would find a high number of normal microbiota?

areas with moisture

what causes body odor?

when normal microbiota metabolizes sweat

diphtheroids

Gram-positive pleomorphic rods

_____________ acnes inhabits hair follicles; anaerobic

Cutibacterium (Propionibacterium)

______________ occupy the skin surface; aerobic

Corynebacterium xerosis

type of yeast that causes dandruff

Malassezia furfur

small, fluid-filled lesions

Vesicles

vesicles larger than 1 centimeter in diameter

Bullae

flat, reddened lesions

Macules

raised lesions

Papules

raised lesions with pus

Pustules

skin rash arising from a disease

Exanthem

rash on mucous membranes arising from a disease

Enanthem

Spherical gram-positive bacteria; form irregular clusters. Some produce coagulase (coagulase +)

Staphylococci

Enzyme that clots fibrin in the blood, used to identify types of staphylococci

coagulase

90% of normal skin microbiota, Healthcare-associated pathogen, Produces biofilm on catheters, and coagulase-negative

Staphylococcus epidermidis

Carried in the nasal passages of 20% of the population, Golden-yellow colonies, Coagulase-positive. May produce damaging toxins and cause sepsis, Avoids host defenses in the skin

Staphylococcus aureus

Secretes proteins and toxins that kill phagocytic cells, MRSA strains of this bacteria are antibiotic-resistant

Staphylococcus aureus

infections of the hair follicles

Folliculitis

Folliculitis of an eyelash

Sty

a type of abscess; localized region of pus surrounded by inflamed tissue

Furuncle (boil)

damage and inflammation of deep tissue from a spreading furuncle

Carbuncle

crusting (nonbullous) sores, spread by autoinoculation

Impetigo

Bullous impetigo, Toxin B causes exfoliation

Scalded skin syndrome

impetigo of the newborn

Pemphigus neonatorum

Fever, vomiting, shock, and organ failure caused by toxic shock syndrome toxin 1 (TSST-1) in the bloodstream

Toxic shock syndrome (TSS)

Produce hemolysins that lyse red blood cells

Streptococcal Skin Infections

Beta-hemolytic streptococci often cause _________

disease

Streptococci differentiated into groups A through T based on _____________________

antigenic cell wall carbohydrates

Produce virulence factors

Group A streptococci (GAS), also known as Streptococcus pyogenes

lyse RBCs

Streptolysins

external to the cell wall; blocks complement activation, enables evasion of phagocytes, kills neutrophils; allows bacteria to adhere to mucous membranes

M proteins

dissolves connective tissue

Hyaluronidase

dissolve blood clots

Streptokinases

S. pyogenes infects the dermal layer of the skin, Causes local tissue destruction and sepsis

Erysipelas

“Flesh-eating” disease, Pyrogenic toxins produced by S. pyogenes acts as a superantigen

Necrotizing fasciitis

Similar to staphylococcal TSS but more deadly

streptococcal TSS

Produces Pyocyanin, a toxic compound, blue-green pus

Pseudomonas aeruginosa

Causes Otitis externa- “Swimmer’s ear”

Pseudomonas aeruginosa

Most common skin disease in humans

acne

Sebum formation is affected by ________, not diet.

hormones

An inflammation of the conjunctiva, Also called red eye or pinkeye

Conjunctivitis

Conjunctivitis is commonly caused by _______________, which is a bacterium unassociated with influenza infections

Haemophilus influenzae

Caused by Chlamydia trachomatis, Bacterium that grows as an obligate intracellular parasite

Inclusion Conjunctivitis:

Spread through swimming pool water, also can be transmitted through birth canal (newborn)

Inclusion Conjunctivitis

Caused by Neisseria gonorrhoeae, Large amount of pus forms; ulceration of corneas results, if untreated can lead to blindness

Ophthalmia neonatorum

Transmitted to a newborn’s eyes during passage through the birth canal, and can be prevented with antibiotics

Ophthalmia neonatorum

Caused by some serotypes of Chlamydia trachomatis, Infection causes permanent scarring; scars abrade the cornea, leading to blindness

Trachoma

Trachoma is treated with ________

Oral azithromycin

Leading cause of blindness worldwide

Trachoma

Papillomas (small skin growths), benign tumor, Transmitted via contact

Warts

Caused by Papilloma virus, Treated with cryotherapy, electrodesiccation, or salicylic acid

Warts

Caused by an Orthropoxvirus, Transmitted via the respiratory route, moves into the bloodstream, and infects many internal organs and the skin

Smallpox

the 2 forms of smallpox

Variola major has 20–60% mortality, Variola minor has <1% mortality

Potential bioterrorism agent but Completely eradicated from the human population by vaccination

Smallpox

caused by Herpesvirus varicella-zoster (human herpesvirus 3) and Transmitted via the respiratory route, Causes pus-filled vesicles after a 10–14-day incubation

Chickenpox (Varicella)

severe complications of chickenpox; vomiting and brain dysfunction

Reye’s syndrome

Virus becomes latent in the dorsal root ganglia

chickenpox virus

Reactivation of the latent varicella-zoster virus that moves from dorsal root ganglia along peripheral nerves to the skin, can prevent it with Zoster vaccine

Shingles (Herpes Zoster)

______ is spread primarily by oral or respiratory routes

HSV -1

_____ is spread primarily sexually, causing genital herpes

HSV -2

_____ of the U.S. population is infected with HSV - 1

90%

_____ remains latent in trigeminal nerve ganglia, Outbreaks are triggered by the sun, stress, or hormonal changes.

HSV-1

_____ remains latent in sacral nerve ganglia near the spine

HSV-2

Viral disease transmitted by the respiratory route. has Cold-like symptoms, macular rash, and Koplik’s spots. infected person shed virus for days before symptoms appear

Measles (Rubeola)

Red spots on the oral mucosa opposite the molars

Koplik’s spots

how do you prevent measles?

Prevented by the MMR (measles, mumps, rubella) vaccine

caused by Rubella virus (Rubivirus), Macular rash and light fever, milder than measles, Transmitted via the respiratory route; 2- to 3-week incubation

German Measles (Rubella)

Fetal damage, deafness, heart defects, mental retardation in 35% of cases, 15% mortality within first year of life

Congenital rubella syndrome

fungal infection of the body

Mycosis

scalp ringworm

Tinea capitis

athlete’s foot

Tinea pedis

ringworm of nails

Tinea unguium

how do you treat fungal infections?

Treatment is usually topical drugs (miconazole and clotrimazole)

Overgrowth of Candida albicans (yeast), Forms pseudohyphae, making it resistant to phagocytosis

Candidiasis

Occurs in the skin and mucous membranes of the genitourinary tract and mouth

Candidiasis

C. albicans infection of the oral cavity

Thrush

Results when antibiotics suppress competing bacteria, or a change occurs in the mucosal pH

Candidiasis

inflammation of the meninges

Meningitis

Initial symptoms of fever, headache, and a stiff neck. Followed by nausea and vomiting

Meningitis

Due to endotoxin (from cell wall of gram-negatives) and cell wall fragments (peptidoglycan, teichoic acid) from gram-positives

Bacterial Meningitis

Viral __________ is more common and mild than the bacterial form

meningitis

Gram-negative aerobic bacteria; normal throat microbiota, Can enter the bloodstream, Occurs mostly in children (6 months to 4 years). Prevented by the Hib vaccine

Haemophilus influenzae Meningitis